A known television tuner will be described with reference to FIG. 3. FIG. 3 is a plan view showing an arrangement of blocks constituting the television tuner. A rectangular metal frame body 21 has four side plates and includes four compartments 25 to 28 divided by shield plates 24. A distribution unit is accommodated in the compartment 25, a tuner unit is accommodated in the compartment 26, a demodulation unit is accommodated in the compartment 27, and a switching unit and a modulation unit are accommodated in the compartment 28. These circuit units are normally arranged on a printed circuit board.
An input connector 22 to which a television signal is input and an output connector 23 for outputting a television signal distributed by the distribution unit are mounted on a short side plate 29 of the metal frame body 21. Also, external terminal groups 31 to 33 protrude from a long side plate 30, which is one of plates adjacent to the short side plate 29. The external terminal groups 31 to 33 are provided for inputting and outputting power and signals supplied to the circuit units. The distribution unit, the switching unit, and the modulation unit are arranged in positions within the sections 25 and 28 along the short side plate 29, and adjacent to the input connector 22 and the output connector 23, respectively. The external terminal group 31 is mounted at the printed circuit board within the compartment 28 in which the switching unit and the modulation unit are arranged.
The distribution unit arranged in the compartment 25 splits the input television signal into two television signals. One of the distributed television signals is input to the tuner unit and the other of the distributed television signals is input to the switching unit. The tuner unit converts the input television signal into an intermediate-frequency signal and outputs the intermediate-frequency signal to the demodulation unit. A demodulated video signal or the like is output to a recorder/player or the like (not shown) via the external terminal group 33.
In contrast, the video signal or the like from the recorder/player or the like is input to the modulation unit via the external terminal group 31 and converted into an RF signal to be input to the switching unit. For playing back, the switching unit outputs the RF signal sent from the modulation unit to the output connector 23. A playback image can be viewed on a television set (not shown) by connecting an external television tuner to the output connector 23. If a playback image is not viewed, the switching unit outputs the distributed signal to the output connector 23. Accordingly, a received television signal can be viewed on the television set. (See, for example, Japanese Unexamined Patent Application Publication No. 10-32514 (FIG. 9).)
In the television tuner described above, the external terminal groups 31 to 33 are inserted into through-holes arranged in a mother board (not shown). Thus, the height from a face of the mother board to the input connector 22 is different from the height from the face of the mother board to the output connector 23. If the television tuner and an external television tuner having a similar shape are arranged in a row on the mother board, since the height of the output connector 23 of the television tuner is different from the height of an input connector of the external television tuner, a cable having connectors at both ends thereof for relaying connection must be used for the connection of the output connector 23 of the television tuner and the input connector of the external television tuner. Thus, an unwanted operation for connection is required, and this increases a parts cost.